http://theprocessreport.com/2010/11/07/what-to-expect-from-desmond-jennings-in-2011/

Player Name      Age     PA      BA      OBP     SLG
Cameron  Maybin  23      322     0.234   0.302   0.361
Jason  Heyward   20      623     0.277   0.393   0.456
Colby  Rasmus    22      520     0.251   0.307   0.407
Travis  Snider   21      276     0.241   0.328   0.419
L. Milledge      23      587     0.268   0.33    0.402
Jay  Bruce       21      452     0.254   0.314   0.453
Justin  Upton    20      417     0.25    0.353   0.463
Delmon  Young    21      681     0.288   0.316   0.408
Jeremy  Hermida  22      348     0.251   0.332   0.368
Grady  Sizemore  22      706     0.289   0.348   0.484
Alexis  Rios     23      460     0.286   0.338   0.383
Rocco  Baldelli  21      684     0.289   0.326   0.416
Corey  Patterson 22      628     0.253   0.284   0.392
Vernon  Wells    23      648     0.275   0.305   0.457
Ruben  Mateo     22      222     0.291   0.339   0.447
Pat  Burrell     23      474     0.26    0.359   0.463

The above data is a collection of each outfielder ranked inside Baseball
America’s annual top 10 list from 2000 until 2009 as Desmond Jennings
himself ranked sixth on the last edition of the list. The seasons noted
represent the first season in which he tallied at least 250 plate appearances
in the majors. Hideki Matsui and Josh Hamilton are absent for obvious reasons
and Ruben Mateo’s first season with 200-plus plate appearances was used
because he never had a season with at least 250 plate appearances, making him
the only legitimate bust amongst the group in the sense that he never
completed a full season.

Where does Jennings fit in? He turned 24 on Halloween eve, meaning he’ll
record his first full season at the oldest age compared to his peers. Age is
not a harbinger of success if Maybin and Rios’ seasons are taken at face
value. Wells and Burrell played quite well, but three of the six best seasons
came from players aged 21 or younger. That’s not because they debuted young,
but because they were incredibly gifted players.

Paring the list down based on Jennings’ position. Only six of the sixteen
can be called centerfielders, although Rios has played his fair share of
center and could have from the start if not for Wells. Regardless, the
results aren’t pretty. First year centerfielders recorded the four worst
on-base percentages and five of the seven worst. Only Sizemore topped a
league average on-base percentage, with Baldelli coming next closest.
Slugging percentages were more of a mixed bag. Maybin and Patterson both
finished under .400, but Wells and Sizemore both finish in the top five, with
Sizemore leading the pack.

Using various filters with the data, a set of projections were former. The
first being a standard average. This is about as crude a measurement as they
come, but no consideration was given to playing time. The next weighed
playing time as a percentage of the whole without considerations for removing
the outliers. The third weighed playing time and removed the two outliers
(Heyward and Maybin). Finally, only center fielders were weighed without
outliers removed. Here are the results:

Average: .266/.330/.424
Weighted average: .269/.329/.426
Weighted average without outliers: .270/.325/.423
Centerfielders weighted average: .273/.315/.433

And here are the results from the real projection systems:

zMLE: .248/.321/.337
CHONE: .263/.331/.384

The advantage these two projections hold is that they actually take Jennings’
 performances into account. Something the first set did not. It just played
with players who share a certain similarity (or two) with Jennings. They both
manage to paint a similar picture: decent batting average, modest on-base
percentage, and then a discrepancy over slugging percentage.

Jennings is going to be more fun in 2011 than his statistics are likely to
show. The teaser at the end of the 2010 season displayed his plate discipline
that transcends his age along with speed that allows him to burn up the
basepaths and play a kamikaze outfield, whether it be center or a corner. It
also showed that Jennings had minimal experience playing underneath a roof
which led to at least one blunder.

The key to enjoying Jennings’ season is to understand that he will not
replace Carl Crawford’s production immediately. That statement is without
disrespect or sinning towards Jennings’ future because it remains bright.
Get excited about Jennings all day and night, just keep expectations in
check. Not every prospect will debut by age 23 and dominate immediately like
Evan Longoria.